LOCATION CATHLAMET WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, isotic, mesic Andic Dystroxerepts
TYPICAL PEDON: Cathlamet silt loam - pasture. (Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
Ap--0 to 5 inches; very dark grayish brown (10YR 3/2) silt loam, dark yellowish brown (10YR 4/4) dry; moderate medium and fine granular structure; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; few fine and many very fine roots; many very fine interstitial pores; slightly acid (pH 6.4); clear smooth boundary. (4 to 7 inches thick)
A2--5 to 12 inches; dark brown (7.5YR 3/4) silt loam, yellowish brown (10YR 5/4) dry; weak medium subangular blocky structure that parts to moderate fine subangular blocky; slightly hard, friable, moderately sticky, moderately plastic and weakly smeary; many fine and very fine roots; many very fine interstitial pores; moderately acid (pH 6.0); gradual wavy boundary. (6 to 11 inches thick)
Bw1--12 to 22 inches; dark brown (7.5YR 4/4) silt loam, yellowish brown (10YR 5/4) dry; moderate coarse medium subangular blocky structure that parts to moderate fine subangular blocky; slightly hard, friable, moderately sticky, moderately plastic and weakly smeary; common very fine tubular pores; moderately acid (pH 6.0); gradual wavy boundary. (10 to 12 inches thick)
Bw2--22 to 60 inches; brown (7.5YR 4/4) silty clay loam, yellowish brown (10YR 5/6) dry; strong coarse subangular blocky structure that parts to moderate fine subangular blocky; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; few fine and very fine roots; many fine and very fine tubular pores; moderately acid (pH 5.6).
TYPE LOCATION: Wahkiakum County, Washington; 200 feet west of SWCD Building Cathlamet, Washington; 600 feet south and 200 feet west of north 1/4 corner of section 12, T. 8 N., R. 6 W.
RANGE IN CHARACTERISTICS: The mean soil temperature ranges from 45 degrees to 54 degrees F. The particle-size control section is silt loam that averages 20 to 30 percent clay and less than 15 percent rock fragments. The soil is dry in the moisture control section for 45 to 60 days following the summer solstice.
The A horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, and chroma of 2 through 4 moist. It is silt loam or silty clay loam. Structure is medium and fine granular or subangular blocky.
The B horizon has hue of 7.5YR or 10YR, and chroma of 4 through 6 dry. It is silt loam or silty clay loam.
COMPETING SERIES: These are the Cathcart, Chelan, Nevat, Pastik, Ponto, Sadie, and Sulsavar series. Cathcart soils are less than 18 percent clay in the control section and are dry for 60 to 70 days. Chelan soils have a neutral or mildly alkaline control section with 6 to 30 percent pumice. Nevat soils are gravelly sandy loam or gravelly fine sandy loam in the control section. Pastik soils have mottles below a depth of 14 inches. Ponto soils are sandy loam or loam with 8 to 18 percent clay and are dry for 65 to 95 days. Sadie soils have a paralithic contact at a depth of 25 to 40 inches. Sulsavar soils have 15 to 35 percent rock fragments in the control section.
GEOGRAPHIC SETTING: Cathlamet soils are on uplands at elevations of 50 to 1,500 feet. Slopes are 1 to 65 percent. These soils formed in material weathered from sandstone. They are in a coastal marine climate with cool, wet winters and cool, dry summers. Mean annual precipitation is 50 to 70 inches. The mean January temperature is about 37 degrees F., the mean July temperature is about 61 degrees F., and the mean annual temperature is 50 degrees F. The frost-free season is 175 to 225 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Germany, Raught and Stimson soils. Germany and Raught soils have an umbric epipedon. Stimson soils are poorly drained.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Cathlamet soils are used for grass, hay and pasture, and timber production. The principal native vegetation is mainly Douglas-fir, western redcedar, red alder, and an understory of salmonberry, sword and brackenferns, and trailing blackberry.
DISTRIBUTION AND EXTENT: Southwestern Washington. The soil is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wahkiakum County, Washington, 1976.
ADDITIONAL DATA: Lab data R75--128 and 129.
REMARKS: Classification changed 4/94 and 1/00 based on revision to Soil Taxonomy.
Classification changed from mixed, mesic Andic Xerochrepts to isotic, mesic Andic Dystroxerepts.